docs: def legend(self, *args, **kwargs):
          """Add a legend.
  
          Parameters
          ----------
          *args
              matplotlib legend args.
          *kwargs
              matplotlib legend kwargs.
  
          Returns
          -------
          legend
          """
          if "fancybox" not in kwargs.keys():
              kwargs["fancybox"] = False
          if "framealpha" not in kwargs.keys():
              kwargs["framealpha"] = 1.
          return super().legend(*args, **kwargs)